Originally Posted by lukydvll
Guess I'll be moving back to a T3 footprint.
Now I need to decide if I should get a T3/T4 or a GT3271.
Any idea which will spool faster and which has more hp potential?
I'd probably get a 50 trim .48 ar with a "stage 3 wheel" if I went T3T4.
I'd like to make an honest 300whp and still have decent response from the turbo.
When will these turbos spool on a 1.8 with 3-inch exhaust?
I think that the T3/T04E has the higher HP potential (only slightly) but that the GT3271 is the better responding turbo. Although this can depend greatly on the actual configuration of the T3/T04E. You don't have to move back to the T3 footprint, the GT3071R is a T25 footprint and will make an honest 300+ RWHP.
This is important, once spooled, the T3/T4 Chinacharger is NOT laggy, it hits hard and fast. It does not lag between shifts or fall out of boost, even short shifting the damn thing and pedaling it out of the hole at the track resulted in a 2.23 60ft time and an 1/8 mile of 8.59@86 and a 1/4 mile of firstname.lastname@example.org and this was with shifting it at 7000 RPM! Compared with my best run that night of 2.16 60 ft and an 1/8 mile of 8.37@89 and a 1/4 mile of email@example.com, it's obvious that the car is not falling too far off the mark even when short shifting. It most definately was in boost the whole time and never gave me the perception of lag...
Now down lower in the RPM range, yes, this turbo is not the happy camper that the T3S60 is. At 4250 RPM on a rather special motor I was making 270 ft/lbs of torque at 14 PSI and 295 RWHP at 10 PSI at 7000. That car was violent and fast too. I would call the motor in my car, built but nothing special, and certainly not the level of effort that was in the T3S60 car.
I think that the bottom line is that if you run the turbo where it's happy, you won't have issues with response. e.g. A T3S60 ghettocharger will be happy from 3000-7000 RPM in top gear, A GT2554R will be happy from damn near 2000-5500 RPM in top gear, and the T3/T4 Chinacharger will be pretty happy from 4500-8500 RPM in top gear assuming you want to make 10 PSI of boost. Like I stated earlier, the more load on the motor, the earlier it will spool. In lower gears I need more RPM to get the turbo to spool. The GT2554R will spool well below 3000 RPM in any gear, the T3S60 ghettocharger spools below 4000 in any gear and the T3/T4 chinacharger will spool by 5000 RPM in any gear.
Most of my time on the throttle is not in first gear, alot is in 2nd and 3rd gear, and by the time I am in 4th gear... well the car is really flying then. 4th gear is taking me past 100 MPH with relative ease. So in reality something that spooled a little earlier might be helpful in daily driving, but as it is the car is just blowing the tire off through 2nd and 3rd gear. Even Jesus couldn't find me enough traction to keep the rear end planted in those two gears. Where it would become painfully obvious that this was a bad pick for a turbo would be at an auto-x event. This is where a large turbo really has no place, it's simply too hard to get the most out of when running in this environment, as highlights why a smaller turbo is sometimes better on the street too. Put the larger turbo on a real track (even something as tight as the Streets of Willow) and it will hand the smaller turbo its ***. I could drive this car plenty fast on any real road course and much faster than I could with the T3S60 or GT2554R at the same boost level.
PS - I am running a 2.5" exhaust... LOL.